Project Fi just got a new benefit announced today. It was announced that US Cellular is going to be an added provider that Project Fi uses. This means better coverage for all Project Fi users. Google has said it will be rolled out in the coming weeks. That means it will most likely need an update for Nexus phones. It is interesting that Google could build phones that were ready for even more networks than they originally planned for with their cellular service.
Looking at the coverage map for US Cellular it looks like their primary network is in the Midwest and Northern California. There is also other partner coverage that shows up on their map, so it will be interesting to see how much more coverage is added to Project Fi. It can range from a few small areas to a lot more. We will see what happens in the coming weeks.